US12016769B2 - Implantable tendon protection systems and related kits and methods - Google Patents

Abstract

An implantable tendon protection system includes a body adapted to be implanted within a bursa overlying a tendon of a patient to protect the tendon. The body may be fixed to the tendon with adhesive, sutures, staples, and/or anchors. A surgical kit is provided with such a tendon protection system and an insertion cannula. Methods of protecting a tendon of a patient are also disclosed.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No. 16/773,220, filed on Jan. 27, 2020, which is a continuation of U.S. application Ser. No. 16/559,134, filed on Sep. 3, 2019, which is a continuation of U.S. application Ser. No. 14/798,921, filed on Jul. 14, 2015, which is a continuation of U.S. application Ser. No. 13/763,414, filed on Feb. 8, 2013, which is a continuation of U.S. application Ser. No. 12/684,774, filed on Jan. 8, 2010, which claims the benefit of U.S. Provisional Application No. 61/253,800, filed on Oct. 21, 2009; 61/184,198 filed on Jun. 4, 2009; 61/162,234 filed Mar. 20, 2009; 61/153,592 filed on Feb. 18, 2009, and 61/143,267 filed on Jan. 8, 2009, the disclosures of each incorporated herein by reference.

FIELD

The present invention relates generally to orthopedic medicine and surgery. More particularly, the present invention relates to methods and apparatus for delivery and fixation of sheet-like implants, such as for treating articulating joints.

BACKGROUND

Injuries to soft tissue, including, for example, musculoskeletal tissue, may require repair by surgical intervention, depending upon factors such as the severity and type of injury. Such surgical repairs can be effected by using a number of conventional surgical procedures, for example, by suturing the damaged tissue, and/or by mounting an implant to the damaged tissue. It is known that an implant may provide structural support to the damaged tissue, and it may also serve as a substrate upon which cells can grow, thus facilitating more rapid healing.

One example of a fairly common soft tissue injury is damage to the rotator cuff or rotator cuff tendons. The rotator cuff facilitates circular motion of the humerus relative to the scapula. Damage to the rotator cuff is a potentially serious medical condition that may occur during hyperextension, from an acute traumatic tear or from overuse of the joint. The most common injury associated with the rotator cuff region is a strain or tear involving the supraspinatus tendon. A tear at the insertion site of the tendon with the humerus, may result in the detachment of the tendon from the bone. This detachment may be partial or full, depending upon the severity of the injury. Additionally, the strain or tear can occur within the tendon itself. Treatment for a strained tendon usually involves physical cessation from use of the tendon, i.e., rest. However, depending upon the severity of the injury, a torn tendon might require surgical intervention as in the case of a full tear or detachment of the supraspinatus tendon from the humerus. Such surgical interventions include debridement, acromioplasty, and various procedures for reconnecting tendons to bone or strengthening damaged tendon to bone connections. Damage to the rotator cuff may also include degeneration. This is a common situation that arises in elderly patients. In degenerative cases there is loss of the superior portion of the rotator cuff with complete loss of the supraspinatus tendon. Similar soft tissue pathologies include tears in the Achilles' tendon, the anterior cruciate ligament and other tendons or ligaments of the knee, wrist, hand, and hip, spine, etc.

Some studies suggest that 85% of people over the age of 65 have some degree of shoulder tendon damage. Well-established procedures exist for repairing fully torn tendons, such as rotator cuff tendons, as previously mentioned. However, adequate treatments do not currently exist for partially torn tendons. There is a large need for less invasive surgical techniques and systems for effecting tendon repair, particularly for the supraspinatus tendon.

SUMMARY OF THE DISCLOSURE

In accordance with aspects of the disclosure, an implantable tendon protection system is provided which comprises a body adapted to be implanted within a bursa overlying a tendon of a patient. The body comprising a tendon engaging surface configured to attach to the tendon. The body may further comprise a sliding surface adapted to slide with respect to the bursa. In some embodiments, the tendon engaging surface comprises adhesive. The body may be configured to be movable between a collapsed state in which the body may be received within a cannula cavity, and a deployed state in which the body may extend across an interior portion of the bursa. In some embodiments, the body is configured to attach to a partially torn tendon. The body may comprise a middle portion that is less flexible than an edge portion.

In some of the above embodiments, the body is constructed from individual layers. A first layer may comprise a sliding surface and a second layer may comprise a tendon engaging surface, a mesh material, a plurality of fibers, and/or a bioabsorbable material. One or more intermediate layers may be located at least partially between the first and second layers. In some embodiments, a cushioning layer is interposed between the first and second layers. An intermediate layer may comprise at least one channel which may fluidly communicate with the tendon engaging surface. In some embodiments the sliding surface has a lower coefficient of friction than that of the tendon engaging surface.

In accordance with other aspects of the disclosure, a surgical kit is provided which comprises a system such as described above and an insertion cannula. The insertion cannula may include a portion configured to enter a body of a patient. This portion includes a cavity for receiving the system when in a collapsed state. The insertion cannula may further comprise a mechanism configured to remove the system from the cavity when the insertion cannula portion is within the body of the patient. The removal mechanism may comprise a push rod at least partially located within the insertion cannula and movable along a longitudinal axis of the insertion cannula.

In accordance with other aspects of the disclosure, methods of protecting a tendon of a patient are disclosed. In some embodiments, the method includes the steps of inserting a device into an at least partially viable bursa of the patient to a position overlying the tendon, and engaging a first surface of the implant with the tendon. The method may further include the step of attaching the device to the tendon. In some embodiments, the attaching step comprises the use of an adhesive. The adhesive may be urged through a channel in the device when the device is positioned within the body of the patient. In some embodiments, the inserting step comprises at least partially receiving the device within a portion of an insertion instrument, inserting the portion of the insertion instrument into the body of the patient, and removing the device from the insertion instrument while the portion is within the body. The device may be caused to assume the deployed state at least partially by introducing a fluid into an inflatable portion of the device.

In some embodiments, the above methods may further comprise the step of delivering a therapeutic or diagnostic agent to tissue adjacent the device. The therapeutic or diagnostic agent may include a drug, anti-inflammatory agent, painkiller, antibiotic, protein, and/or a hormone.

In some embodiments, a second surface of the device is deployed to slide relative to the bursa. The device may serve to protect a damaged portion of the tendons. In some embodiments, the device does not substantially reinforce the engaged tendons by transmitting a significant load of the tendons. The device may serve to remove a stimulus from nerves in the engaged tendons. The removed stimulus may include one or more of pressure, temperature, chemical, electrical and inflammation stimulus. In some embodiments the device is not sutured to the tendons or other tissue. The inserting step may comprise the use of an arthroscopic instrument. In some embodiments the tendon comprises a partially torn tendon. The attaching step may comprise securing the device to the tendon using a plurality of anchors.

In accordance with other aspects of the disclosure, a method is provided which comprises identifying a partially torn portion of a tendon and covering the partially torn portion of the tendon. In some embodiments a device may be positioned over the partially torn portion of the tendon and fixed to the tendon. The device may be fixed to the tendon with adhesive, sutures, staples, and/or anchors. Covering the partially torn portion of the tendon may spread impinging forces across a surface area of the device. In some embodiments a therapeutic agent that promotes growth of tissue into pores defined by the device may be delivered. The therapeutic agent may promote encapsulation of the device within a cellular encapsulation layer. The therapeutic agent may induce the growth of synovial cells on an outer surface of the device. The therapeutic agent may induce the growth of bursa cells on an outer surface of the device. The therapeutic agent may desensitize stimulated nerve receptors proximate the partially torn portion of the tendon. The therapeutic agent may promote the growth of a cellular encapsulation barrier over the partially torn portion of the tendon.

In some embodiments, covering the partially torn portion of the tendon inhibits the partially torn portion of the tendon from becoming a tear extending through a total thickness of the tendon. Covering the partially torn portion of the tendon may inhibit physical stimulus of the partially torn portion by adjacent tissues. Covering the partially torn portion of the tendon may protect damaged tendon fibers from mechanical agitation by adjoining tissues. Covering the partially torn portion of the tendon may alleviate pain, which in turn may restore shoulder function. In some embodiments, covering the partially torn portion of the tendon protects the partially torn portion of the tendon. Covering the partially torn portion of the tendon may prevent abrasion of the partially torn portion of the tendon. Covering the partially torn portion of the tendon may reduce friction between the partially torn portion of the tendon and adjacent tissues. Covering the partially torn portion of the tendon may cushion forces applied to the partially torn portion of the tendon by adjacent tissues.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG.1 is an anterior view showing the upper torso of a patient with the left shoulder shown in cross-section.

FIG.2 is an enlarged, cross-sectional view showing the left shoulder depicted inFIG.1.

FIG.3 is an enlarged, cross-sectional view showing an exemplary implantable device in accordance with aspects of the invention inserted into the shoulder.

FIG.4 is an enlarged, oblique, cross-sectional view showing an exemplary cannula inserted into the bursa of the shoulder.

FIG.5 is an enlarged, oblique, cross-sectional view showing an exemplary delivery system inserted into the shoulder.

FIG.6 shows the delivery system ofFIG.5 with the sheath retracted.

FIG.7 shows the delivery system ofFIG.5 with the implantable device completely deployed.

FIG.8 shows the implantable device in place with the delivery system ofFIG.5 removed.

FIG.9 is an exploded isometric view illustrating an exemplary implantable device.

FIG.10 is a stylized block diagram illustrating an exemplary implantable device coupled to a syringe.

FIGS.11A,11B, and11C are a series of isometric views illustrating the deployment of an exemplary implantable device.

FIG.12 is a plan view illustrating an exemplary implantable device.

FIG.13 is a side cross-sectional view taken along line A-A inFIG.12.

FIG.14 is a side cross-sectional view taken along line A-A inFIG.12 and illustrating the device ofFIG.12 anchored to a tendon.

DETAILED DESCRIPTION

The following detailed description should be read with reference to the drawings in which similar elements in different drawings are numbered the same. The drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the invention.

FIG.1 is a stylized anterior view of apatient28. For purposes of illustration, ashoulder26 ofpatient28 is shown in cross-section inFIG.1.Shoulder26 includes ahumerus24 and ascapula23. The movement ofhumerus24 relative toscapula23 is controlled by a number of muscles including: the deltoid, the supraspinatus, the infraspinatus, the subscapularis, and the teres minor. For purposes of illustration, only the supraspinatus30 is shown inFIG.1. With reference toFIG.1, it will be appreciated that adistal tendon22 of the supraspinatus30 meetshumerus24 at aninsertion point32.

FIG.2 is an enlarged cross sectional view ofshoulder26 shown in the previous figure. InFIG.2, ahead36 ofhumerus24 is shown mating with a glenoid fossa ofscapula23 at a glenohumeral joint38. The glenoid fossa comprises a shallow depression inscapula23. A supraspinatus30 and adeltoid34 are also shown inFIG.2. These muscles (along with others) control the movement ofhumerus24 relative toscapula23.

Adistal tendon22 ofsupraspinatus30 meetshumerus24 at aninsertion point32. In the embodiment ofFIG.2,tendon22 includes a damagedportion140 located nearinsertion point32.Damaged portion140 includes atear142 extending partially throughtendon22. Tear142 may be referred to as a partial thickness tear.Tendon22 ofFIG.2 has become frayed. A number ofloose tendon fibers144 are visible inFIG.2.

Scapula23 includes anacromium21. InFIG.2, asubacromial bursa20 is shown extending betweenacromium21 ofscapula23 andhead36 ofhumerus24. InFIG.2,subacromial bursa20 is shown overlayingsupraspinatus30.Subacromial bursa20 is one of more than 150 bursae found the human body. Each bursa comprises a fluid filled sac. The presence of these bursae in the body reduces friction between bodily tissues. Injury and/or infection of the bursa can cause it to become inflamed. This condition is sometimes referred to as bursitis.

FIG.3 is an additional cross sectional view ofshoulder26 shown in the previous figure. In the embodiment ofFIG.3, adevice4 has been implanted insidesubacromial bursa20.Device4 comprises abody150.Body150 is adapted to be implanted within a bursa overlying a tendon of a patient.

InFIG.3,body150 ofdevice4 is shown overlayingtear142. In the exemplary embodiment ofFIG.3,body150 comprises afirst side152 and a second side154.First side152 comprises a slidingsurface156 and second side154 comprises a tendon engaging surface158. Slidingsurface156 is adapted to slide with respect to adjacent tissues (e.g., bursa tissue). Tendon engaging surface158 is configured to attach to a tendon.

In the exemplary embodiment ofFIG.3,fibers144 oftendon22 are fixed todevice4 by an adhesive160.Adhesive160 is illustrated using dots inFIG.3. With reference toFIG.3, it will be appreciated that adhesive160 permeates a portion ofdevice4. Some exemplary methods in accordance with the present detailed description include injecting an adhesive into channels defined by a device so that the adhesive exits a plurality of apertures defined by a tissue engaging layer of the device. The adhesive may elute over a large area to affix the device to a tendon. Some additional exemplary methods in accordance with the present detailed description include injecting a therapeutic agent (e.g., a drug) into channels defined by a device so that the therapeutic agent exits a plurality of apertures defined by a tissue engaging layer of the device.

FIG.4 is an isometric view of ashoulder26.Shoulder26 includes ahumerus24 and ascapula23.Humerus24 comprises ahead36 having a generally spherical surface.Head36 ofhumerus24 mates with a shallow depression defined by thescapula23 at a glenohumeral joint38. InFIG.4, adistal tendon22 of a supraspinatus30 is shown meetinghumerus24 at an insertion point. Supraspinatus30 (along with a number of other muscles) controls the movement ofhumerus24 relative toscapula23.

InFIG.4, asubacromial bursa20 is shown overlaying a portion ofsupraspinatus30.Subacromial bursa20 comprises a fluid filled sac that acts to reduce friction between tissues in the body. InFIG.4,subacromial bursa20 is shown extending between a portion ofsupraspinatus30 and anacromium21 ofscapula23. In the embodiment ofFIG.4, the distal end of acannula162 has been inserted into the interior ofbursa20.Cannula162 may be inserted, for example, near a site where tendon damage exists.Cannula162 includes a shaft164 defining a lumen and ahub166 that is fixed to a proximal end of shaft164. In the embodiment ofFIG.4, the lumen defined bycannula162 fluidly communicates with an interior ofsubacromial bursa20. Accordingly, a device may be placed in the interior ofsubacromial bursa20 by advancing that device through the lumen defined bycannula162.

FIG.5 is an additional isometric view ofshoulder26 shown in the previous figure. Adelivery system170 is shown inFIG.5.Delivery system170 ofFIG.5 comprises asheath3, abarrel2, and aplunger1. In the embodiment ofFIG.5, adevice4 is disposed insidesheath3. Some methods in accordance with the present detailed description may include the step of causing the body of a device to assume a collapsed shape and inserting the body of the device into a sheath. The sheath and the body of the device may both be inserted into a bursa. Once inside the bursa, the body may assume a deployed shape.

It is to be appreciated that the length ofdelivery system170 may vary from that shown inFIG.5 without deviating from the spirit and scope of the present detailed description. In useful some embodiments, a portion ofdelivery system170 may extend through a cannula (e.g., the cannula shown in the previous figure). The cannula may guide the distal end ofdelivery system170 to a target site.

FIG.6 is an additional isometric view showingdelivery system170 shown in the previous figure. In the embodiment ofFIG.6,sheath3 ofdelivery system170 has been retracted fromdevice4, exposingdevice4. In other embodiments,sheath3 may remain stationary whiledevice4 is extended from within the sheath, ordevice4 may be deployed with a combination of movements of the sheath and the device. In some useful embodiments,device4 assumes a generally cylindrical shape while disposed insidesheath3. In the embodiment ofFIG.6, deployment ofdevice4 has been initiated. Accordingly,device4 is shown assuming a somewhat enlarged shape inFIG.6.

FIG.7 is an additional isometric view showingdelivery system170 shown in the previous figure. InFIG.7,device4 is shown assuming a completely deployed shape. In the exemplary embodiment ofFIG.7,device4 is generally plate-shaped and circular when fully deployed. In some advantageous embodiments, the body ofdevice4 is flexible.

Some exemplary methods in accordance with the present detailed description include injecting an adhesive into channels defined by a device so that the adhesive exits a plurality of apertures defined by a tissue engaging layer of the device. The adhesive may elute over a large area to affix the device to a tendon.Delivery system170 may be withdrawn fromshoulder26 after the delivery ofdevice4 is complete.

FIG.8 is an additional cross sectional view ofshoulder26 shown in the previous figure. In the embodiment ofFIG.8,device4 has been implanted insidesubacromial bursa20. InFIG.8,device4 is shown overlaying a portion ofdistal tendon22 ofsupraspinatus30. In the exemplary embodiment ofFIG.8,device4 comprises abody150 having afirst side152 and a second side154.First side152 comprises a slidingsurface156 and second side154 comprises a tendon engaging surface158. In the embodiment ofFIG.8,body150 has been positioned so that tendon engaging surface158 engagestendon22. Tendon engaging surface158 may be fixed todistal tendon22, for example, with an adhesive. Whendevice4 is overlayingtendon22 as shown inFIG.8,device4 provides a slidingsurface156 facing away fromtendon22.

FIG.9 is an exploded isometric view illustrating anexemplary device304 in accordance with the present detailed description. In the exemplary embodiment ofFIG.9,device304 comprises abody350 including a first layer372, asecond layer374, a firstintermediate layer376, and a secondintermediate layer378.

Whendevice304 is overlayingtendon22, first layer372 ofdevice304 provides a slidingsurface356 facing away from the tendon. In the exemplary embodiment ofFIG.9,second layer374 comprises a biocompatible material for use against the tendon surface. In the embodiment ofFIG.9,second layer374 defines a plurality ofapertures380. In one exemplary embodiment,second layer374 comprises a mesh material. In some embodiments,second layer374 may comprise a plurality of fibers. The fibers may be interlinked with one another. When this is the case,second layer374 may comprise a plurality of apertures comprising the interstitial spaces between fibers. Various processes may be used to interlink the fibers with one another. Examples of processes that may be suitable in some applications including weaving, knitting, and braiding.

In some useful embodiments,second layer374 comprises one or more bioabsorbable materials. Examples of bioabsorbable materials that may be suitable in some applications include those in the following list, which is not exhaustive: polylactide, poly-L-lactide (PLLA), poly-D-lactide (PDLA), polyglycolide (PGA), polydioxanone, polycaprolactone, polygluconate, polylactic acid-polyethylene oxide copolymers, modified cellulose, collagen, poly(hydroxybutyrate), polyanhydride, polyphosphoester; poly(amino acids), poly(alpha-hydroxy acid) or related copolymers materials.

In the exemplary embodiment ofFIG.9, secondintermediate layer378 comprises a plate defining a plurality of channels. Channels382 of secondintermediate layer378 andapertures380 ofsecond layer374 may allow a fluid to elute over a large area todevice304 to a tendon. Secondintermediate layer378 may also distribute stresses acrossdevice304. When pressure from adjacent tissues is applied todevice304, the device will spread that pressure across an area of a tendon covered bydevice304. This function helpsdevice304 to reduce stimulus to nerves in the covered tendon.

Asecond inlet386 is visible inFIG.9. An interior ofsecond inlet386 is in fluid communication with channels382 of secondintermediate layer378. Whendevice304 is in an assembled state, channels382 fluidly communicate withapertures380 defined bysecond layer374. Fluid may be injecting into channels382 and throughapertures380 by injecting the fluid intosecond inlet386. In one method in accordance with the present detailed description, an adhesive fluid is injected into channels382. The adhesive fluid may elute over a tissue engaging area ofdevice304 to affixdevice304 to a tendon.

In the exemplary embodiment ofFIG.9, firstintermediate layer376 comprises a plurality of sheets defining acavity388. Various fluids may be injected intocavity388. Some exemplary methods in accordance with the present detailed description may include changing the shape of shape ofdevice304. The shape ofdevice304 may be changed, for example, by injecting fluid intocavity388. Afirst inlet384 is shown inFIG.9. An interior offirst inlet384 is in fluid communication withcavity388 of firstintermediate layer376. Fluid may be injected intocavity388 by injecting the fluid intofirst inlet384.

FIG.10 is a stylized block diagram illustrating anexemplary device504 in accordance with the present detailed description. In the exemplary embodiment ofFIG.10,device504 comprises a body550 including afirst layer572, asecond layer574, a firstintermediate layer576, and a secondintermediate layer578.

In the embodiment ofFIG.10, secondintermediate layer578 comprises a plurality of flow channels. A tube590 defines a lumen that is in fluid communication with the flow channels of intermediate layer. In the embodiment ofFIG.10, a proximal end of tube590 is coupled to asyringe592.Syringe592 comprising abarrel2 and aplunger5. A fluid594 is disposed inbarrel2.Plunger5 ofsyringe592 is capable of urgingfluid594 out ofbarrel2, through tube590, through secondintermediate layer578, and throughsecond layer574. The flow offluid594 through secondintermediate layer578 andsecond layer574 is illustrated using a plurality of arrows inFIG.10.Fluid594 may be urged through a plurality of apertures defined bysecond layer574.Fluid594 that has exitedsecond layer574 is represented by a number of fluid drops in the stylized block diagram ofFIG.10.

Some exemplary methods in accordance with the present detailed description may include the step of delivering a therapeutic or diagnostic agent to tissue adjacent a device such as, for example,device504 ofFIG.10. The fluid may comprise various therapeutic or diagnostic agents. Examples of therapeutic or diagnostic agents that may be suitable in some applications include drugs, anti-inflammatory agents, painkillers, antibiotics, proteins, and hormones.

FIGS.11A,11B, and11C are a series of isometric views illustrating the deployment of adevice4. Some methods in accordance with the present detailed description may include the step of causing the body of a device to assume a collapsed shape and inserting the body of the device into a sheath. The sheath and the body of the device may both be inserted into a bursa. Once the body is inside the bursa, the body may be urged to assume a deployed shape and/or self-deploy.

In the embodiment ofFIG.11A,device4 is disposed inside asheath3 of adelivery system170. The body ofdevice4 may be wrapped at least partially around itself to assume a generally collapsed shape. In some useful embodiments, the body ofdevice4 is capable of assuming a generally cylindrical collapsed shape while disposed inside a lumen ofsheath3. The body ofdevice4 may also be folded to assume a generally collapsed shape.

In the embodiment ofFIG.11B,sheath3 has been retracted fromdevice4.Device4 can be seen disposed outside ofsheath3 inFIG.11B. In the embodiment ofFIG.11B, deployment ofdevice4 has been initiated. Accordingly,device4 is shown assuming a somewhat enlarged shape inFIG.11B.

In the embodiment ofFIG.11C,device4 has been fully deployed. In the exemplary embodiment ofFIG.11,device4 is generally plate shaped when fully deployed. InFIG.4, the outer edge ofdevice4 is shown having a generally circular shape. In the exemplary embodiment ofFIG.11,device4 comprises abody150 having afirst side152 and a second side154.First side152 comprises a slidingsurface156 and second side154 comprises a tendon engaging surface158. In some useful methods,device4 is oriented over a tendon so that tendon engaging surface158 engages the tendon.

FIGS.12 through14 show anadditional device700 in accordance with the present detailed description.Device700 may be used, for example, to cover an injured portion of a tendon.FIG.12 is a top view ofdevice700.FIG.13 is section view ofdevice700 taken along section line A-A shown inFIG.12.FIG.14 is a section view similar toFIG.13showing device700 in place overtendon736.

As best seen inFIG.13,exemplary device700 comprises a base702 having a firstmajor side704 and a secondmajor side706 that is opposite firstmajor side704. In this embodiment, firstmajor side704 comprises a generallyconcave surface720 and secondmajor side706 comprises a generallyconvex surface722. Asheet724 ofdevice700 may be provided to overlay firstmajor side704 ofbase702 and generally conforms to the shape ofconcave surface720.

As shown inFIG.13,sheet724 ofdevice700 defines acavity726. In some useful embodiments,cavity726 is dimensioned to receive a portion of a suprapinatus tendon overlying the head of a humerus. In the exemplary embodiment ofFIG.13,cavity726 has a generally hemispherical shape. It will be appreciated that the radius ofcavity726 may vary acrosscavity726 without deviating from the spirit and scope of the present description. With reference to the figures, it will be appreciated that askirt portion728 ofsheet724 extends beyondbase702 in this embodiment.

In some useful embodiments,sheet724 comprises a material defining a plurality of pores that encourage tissue growth therein. A coating that encourages tissue growth or ingrowth may be applied to the surfaces ofsheet724. It will be appreciated thatsheet724 may comprise various pore defining structures without deviating from the spirit and scope of the present description. In some embodiments, thesheet724 has a pore size in the range of 150 to 200 microns. The porosity may be about 50 percent. Examples of pore defining structures that may be suitable in some applications include open cell foam structures, mesh structures, and structures comprising a plurality of fibers. In some embodiments, the fibers may be interlinked with one another. Various processes may be used to interlink the fibers with one another. Examples of processes that may be suitable in some applications include weaving, knitting, and braiding.

Device700 includes a plurality ofanchors730. In the exemplary embodiment shown, each anchor comprises acoil732. It will be appreciated that anchors730 may comprise other elements without deviating from the spirit and scope of the present description. Examples of anchoring elements that may be suitable in some applications include: coils, barbs, hooks, stables, suture pads, and sutures. In the embodiment of FIG.13, each anchor is disposed in alumen734 defined bybase702. Some methods in accordance with the present description may include the step of rotatinganchors730 to screw the anchors into tissue (e.g., tendon tissue) for fixingdevice700 to that tissue. A flexible catheter or other suitable driver may used to rotateanchors730. For example, a catheter (not shown) may be removably inserted into each of thelumens734 in turn, accessing each lumen through acentral recess735 located in secondmajor side706 ofbase702. In some embodiments,anchors730 threadably engage with interior surfaces oflumens734 to facilitate advancement of the anchor into tissue.

InFIG.14,device700 is shown overlaying atendon736. To placedevice700 overtendon736,device700 may be configured to be collapsible so that it may be inserted into the body arthroscopically, similar to the previously described devices. For example,device700 may be collapsed like an umbrella, with itslumens734 being substantially parallel and the material betweenlumens734 forming inwardly folding pleats when in the collapsed state.

In the embodiment ofFIG.14, eachcoil732 is shown extending out of alumen734 and intotendon736.Tendon736 may be, for example, a supraspinatus tendon. With reference toFIG.14, it will be appreciated that the diameter of eachcoil732 has become enlarged as it exits alumen734. In some useful embodiments, eachcoil732 is biased to assume an increased diameter as it exits alumen734. InFIG.14, eachcoil732 is shown extending through askirt portion728 ofsheet724 that extends beyondbase702, and then intotendon736 to secure or assist in securingdevice700 to the tendon. In this embodiment, the middle and edge portions are configured to help distract a humeral head in abduction.

In other embodiments (not shown), a device may be provided with lumens having a steeper or shallower angle relative totendon736. While theexemplary device700 shown inFIGS.12-14 employs six anchors, other devices constructed in accordance with aspects of the present description may be provided with a smaller or larger number of anchors. In other embodiments, sutures, staples, adhesive and/or other fasteners may be used in conjunction with or instead ofanchors730 to securedevice700 to the underlying tissue. Preformed holes may also be provided insheet724 to allowanchors730 to pass through. In other embodiments,sheet724 may be omitted. In still other embodiments, the device may have more or less of a cup shape, be generally flat, or inverted such that the anchors emerge from the convex side rather than the concave side. The device may be oblong, curved in only one dimension, or be saddle-shaped, depending on the particular anatomy it is designed to protect.

An implantable device such as previously described may be placed over a partial tear in a tendon. In some embodiments, the device may be implanted over a tendon having micro-tear(s), abrasions and/or inflammation. Left untreated, minor or partial tendon tears may progress into larger or full tears. According to aspects of the present invention, a small or partial tear may be treated by protecting it with an implantable device as described above. Such early treatment can promote healing and prevent more extensive damage from occurring to the tendon, thereby averting the need for a more involved surgical procedure.

The implanted device may serve to protect a tendon from a stimulus. The stimulus may comprise one or more of the following: pressure, friction, temperature, electrical or chemical stimulus. In some embodiments, the device does not supplant or share any substantial load borne by a tendon, but serves to protect the tendon to facilitate healing.

In some embodiments, a bursa overlying a tendon is left substantially intact as the device is implanted over the tendon. This may be accomplished by creating a small incision or puncture through one wall of the bursa through which the device delivery cannula may be placed. The bursa may be filled with saline or similar fluid during the procedure to keep it inflated, thereby providing sufficient operating space for deploying and attaching the implantable device. After the device is implanted and the delivery cannula is removed, the opening in the bursa may be closed, such as with one or more sutures. Alternatively, it is believed that the bursa may form closure tissue by itself post-operatively. Such bursa growth may be stimulated by movement of the tendon and/or bursa relative to surrounding tissue.

In other embodiments, a portion or all of the bursa may be removed during the implantation procedure. In these embodiments, the implantable device may be sized and positioned to facilitate the bursa reforming naturally in its original location after the procedure.

As previously indicated, the implantable device may comprise an absorbable material. In some embodiments, the purpose of the device is to protect an injured portion of a tendon during healing, provide a scaffolding for new tissue growth, and/or temporarily share some of the tendon loads. The device may induce additional tendon tissue formation, thereby adding strength and reducing pain, micro strains and inflammation. When the device is applied to a structurally intact, partially torn tendon, the initial loading of the device may be carried by native tendon tissue until collagen is formed during the healing process. In some embodiments, organized collagen fibers are created that remodel to neo tendon with cell vitality and vascularity. Initial stiffness of the device may be less than that of the native tendon so as to not overload the fixation while tendon tissue is being generated.

The implantable device may be configured to allow loading and retention of biologic growth factors. The device and/or the growth factors may be configured to controllably release the growth factors. The device may be configured to allow transmission of body fluid to remove any degradation bi-products in conjunction with a potential elution profile of biologics. The device should degrade over time with minimal inflammatory response. For example, particulate matter that may result from degradation should not generate synovitus in the joint.

In one exemplary embodiment, the implantable device has a diameter of about 22 mm, and has directionally specific mechanical properties. In another embodiment, the device is generally rectangular with a width of about 20 mm, a length of about 40 mm, and a thickness of about 1 mm. In another embodiment, the device has a length of about 30 mm. These latter two arrangements provide a 20 mm2 cross-sectional area transverse to the load direction.

It is desirable in some situations to generate as much tissue as possible within anatomical constraints. In some cases where a tendon is degenerated or partially torn, tendon loads are relatively low during early weeks of rehabilitation. For example, the load may be about 100 N. The strain in the tendon due to the load during rehabilitation can be about 2%. In some of these cases, the implantable device can be designed to have an ultimate tensile strength of at least about 5 MPa. The tensile modulus can be designed to be no more than about 50 MPa and no less than about 20 MPa. The compressive modulus can be designed to be at least about 0.5 MPa. With a tensile modulus of 50 MPa, in order for the scaffold to strain 2% in conjunction with the degenerated tendon, the stress on the scaffold will be about 1.0 MPa. With an ultimate tensile strength of 5 MPa, the strength of the scaffolding of the implantable device when first implanted will be about five times the expected loads. With a cross-sectional area of 20 mm2, the load on the scaffold will be 20 N. Thus, from a load sharing perspective, the scaffold will carry about 20% of the load to experience 2% strain.

A published value for the compressive modulus of the supraspinatus tendon is in the range of 0.02-0.09 MPa (J Biomech Eng 2001, 123:47-51). The scaffold provided by the implantable device should have a higher compressive modulus than the tendon to prevent collapse of pores in the scaffold. A compressive modulus of 0.5 MPa would be about five times greater than the tendon.

The tissue within the device scaffold will typically be developing and organizing during the first one to three months after implantation, so load sharing with the scaffold is desired in some embodiments. After three months the tissue will typically be remodeling, so the mechanical properties of the scaffold should gradually decline to zero to enable the new tissue to be subjected to load without the scaffold bearing any of the load. If the scaffold loses modulus faster than it loses strength, then the relative loads on the scaffold will be less at three months than when first implanted. For example, if the modulus of the scaffold drops 50% to 25 MPa at three months, then 2% strain of the scaffold would require a stress of only about 0.5 MPa. At the same time, if the strength of the scaffold drops about 30% to 3.5 MPa, then the strength of the scaffold will be about seven times the anticipated loads at three months, compared to about five times when first implanted. Therefore, with the design criteria provided above, tensile failure of the scaffold during the first three months should be unlikely. Accordingly, the following specifications for degradation rate are recommended in some embodiments: an ultimate tensile strength of at least 70% strength retention at three months; tensile and compressive modulus of at least 50% strength retention at three months; and no minimum specification for strength and modulus at 6 months. The device may be designed to have a degradation profile such that it is at least 85% degraded in less than 1 to 2 years after implantation.

Cyclic creep is another design constraint to be considered in some embodiments. A strain of about 2% with a 40 mm long scaffold will result in an elongation of about only 0.8 mm. Therefore, very little cyclic creep can be tolerated in these embodiments to ensure that the scaffold will undergo strain with each load cycle. A test where a proposed scaffold design is cyclically strained to 2% at 0.5 Hz for 1 day provides 43,200 cycles, which likely exceeds the number of cycles experienced in three months of rehabilitation of a patient's joint. Incorporation of relaxation times should be considered in such testing. In some embodiments, a maximum of about 0.5% creep is an acceptable specification.

Material(s) used in the implanted device should be able to withstand the compression and shear loads consistent with accepted post surgical shoulder motions. The perimeter of the device may have different mechanical properties than the interior of the device, such as for facilitating better retention of sutures, staples or other fastening mechanisms. The material(s) may be chosen to be compatible with visual, radiographic, magnetic, ultrasonic, or other common imaging techniques. The material(s) may be capable of absorbing and retaining growth factors with the possibility of hydrophilic coatings to promote retention of additives.

While the systems, kits and methods disclosed above have been discussed relative to protecting tendons in shoulder joints, they may also be utilized to protect tendons in other articulating joints such as the knee, elbow and ankle.

While exemplary embodiments of the present invention have been shown and described, modifications may be made, and it is therefore intended in the appended claims to cover all such changes and modifications which fall within the true spirit and scope of the invention.

Claims (15)

What is claimed is:

1. A method of repairing a tendon, comprising:

placing a sheet-like implant over the tendon; and

thereafter, delivering an adhesive fluid to the sheet-like implant such that the adhesive fluid flows within the sheet-like implant to the tendon; and

securing the sheet-like implant to the tendon with the adhesive fluid.

2. The method ofclaim 1, further comprising:

eluting the fluid through a plurality of apertures formed in the sheet-like implant.

3. The method ofclaim 2, wherein the sheet-like implant includes a plurality of interlinked fibers with interstitial spaces defined therebetween.

4. The method ofclaim 3, wherein the interstitial spaces define the plurality of apertures.

5. The method ofclaim 2, further comprising:

injecting the adhesive fluid through a plurality of channels extending through the sheet-like implant, the plurality of channels being in fluid communication with the plurality of apertures.

6. The method ofclaim 5, wherein the channels are positioned between a first layer and a second layer of the sheet-like implant.

7. The method ofclaim 1, wherein the adhesive fluid is delivered to the sheet-like implant from a syringe.

8. The method ofclaim 7, wherein the sheet-like implant includes a fluid inlet fluidly coupled to the syringe.

9. A method of repairing a tendon, comprising:

placing a sheet-like implant over the tendon such that a tissue engaging area of the sheet-like implant contacts the tendon;

delivering an adhesive fluid to an interior of the sheet-like implant; and

eluting the adhesive fluid from the interior of the sheet-like implant through the tissue engaging area of the sheet-like implant such that the adhesive fluid flows out of the sheet-like implant into contact with the tendon; and

securing the sheet-like implant to the tendon with the adhesive fluid.

10. The method ofclaim 9, wherein the adhesive fluid is delivered to the sheet-like implant from a syringe.

11. The method ofclaim 9, further comprising:

injecting the adhesive fluid through a plurality of channels extending through the sheet-like implant.

12. The method ofclaim 11, wherein the plurality of channels are in fluid communication with a plurality of apertures defined in the tissue engaging area of the sheet-like implant.

13. The method ofclaim 12, wherein the sheet-like implant includes a plurality of interlinked fibers with interstitial spaces defined therebetween, wherein the interstitial spaces define the plurality of apertures.

14. A method of repairing a tendon, comprising:

placing a sheet-like implant over the tendon such that a tissue engaging area of the sheet-like implant contacts the tendon;

injecting an adhesive fluid into the sheet-like implant; and

adhering the sheet-like implant to the tendon with the adhesive fluid eluting from a plurality of apertures in the tissue engaging area of the sheet-like implant.

15. The method ofclaim 14, further comprising:

injecting the adhesive fluid from a syringe through a plurality of channels extending through the sheet-like implant to the plurality of apertures.

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